For one, if you're building less houses, you're not receiving the experience points for building that house, that means fewer shipments.
Well, actually, there are some real flaws with this card. If you were under attack, it would be a breeze to maintain production. You won't need as much wood for houses, it's easy to unhouse yourself when you're maxing out. Upon first glance, this card looks like it's actually pretty good. This card makes every house you build worth 30 population instead of the ordinary 10 population. First lets start with cards you should avoid, and why you should avoid them.